Posted
by
Soulskill
on Friday June 04, 2010 @12:59PM
from the time-for-cassini-2 dept.

Calopteryx writes "New Scientist reports that in 2005, researchers predicted two potential signatures of life on Titan. Now, thanks to research done with the help of the Cassini spacecraft, both have been seen, although non-biological chemical reactions could also be behind the observations. NASA's writeup has further details: 'One key finding comes from a paper online now in the journal Icarus [abstract] that shows hydrogen molecules flowing down through Titan's atmosphere and disappearing at the surface. Another paper online now in the Journal of Geophysical Research maps hydrocarbons on the Titan surface and finds a lack of acetylene. This lack of acetylene is important because that chemical would likely be the best energy source for a methane-based life on Titan, said Chris McKay, an astrobiologist at NASA Ames Research Center, Moffett Field, Calif., who proposed a set of conditions necessary for this kind of methane-based life on Titan in 2005. One interpretation of the acetylene data is that the hydrocarbon is being consumed as food. But McKay said the flow of hydrogen is even more critical because all of their proposed mechanisms involved the consumption of hydrogen.'"

It sounded like it was referring to heretofore unknown kinds of life that use completely different chemical processes than we see on earth, with the possible exception of really weird stuff that you find at the bottom of the ocean. Nothing that would have gotten onto our probe, in any case.

I think you misunderstand. The mechanisms that would cause life to consume the substances that are 'missing' are totally alien to life as we know it, but fit the model for methane based life very well. It could well be that there are non-biological chemical processes doing it, but the odds of it being from any contamination from Huygens is astronomically remote. Hugyens was also very, very carefully sterilized. Granted, a microbe or two might have made it to Titan, where it would most likely die rather than reproduce.

I do see your point and we need to continue to be careful, but I see nothing in these findings that makes the Hugyens discussion at all relevant to this story.

Actually I don't think his is a bad point. First off, we DON'T understand the metabolisms of most microbes on earth: most CAN'T be cultured in a lab because of this, experimented with, etc. etc.: only a little subset of the entire known microbial biota are even available for us to research. Beyond this, however, the known range of things that microbes can eat is expanding beyond our wildest imaginings: and not just on the bottom of oceans. That's why we now have microbes to use to eat oil spills, nuclear waste, and even metals (ummm....iron and steal, yum!). Not kidding about the bacteria that eat metals, by the way, which incidentally...DO IT BY HYDROGEN AND ELECTRON EXCHANGES. There's all sorts of stuff that one can tell you haven't even considered from the comment you just made: you need to do more dreaming "dream[er]...".

P.S. bacteria have survived in the vaccum of space on the moon, so "[they] would most likely die" is also not a very informed statement. I don't mean to be too insulting here, just very frank about the state of knowledge on these things vs. what you wrote: that is rose to "5, Insightful" just demanded the bio nerd in me to respond.

Not only the impact of Huygens or any future probe [wikipedia.org] would be miniscule - with certainly quite different chemistries of Earth life and any possible Titan life, plus with very precise list of probe components and "payload", there should be little chance of confusion...

I have a pretty good suspicion that most life on Earth, even the extremophiles, would have a rather hard time living on Titan. The temperatures are extremely low, the solar energy and even Saturn's energy are much less combined than on Earth. The kind of biochemistry would be quite different than found here. I'm not saying it's entirely impossible, but I think a planet like Mars would be far more likely to be able to harbor certain hardy organisms from Earth than a place like Titan. My understanding is

If it uses DNA or RNA (quite unlikely) then I guess that contamination is possible. But since we'd want to totally sequence whatever replicator molecule it used, it would be reasonably easy to determine whether contamination is even a reasonable hypothesis.

Remember, all life on this planet is related to a measurable degree. If it's related, then we can figure out what it's most closely related to, and how long ago it diverged. (Remember, when the proto-moon collided with the earth it quite likely emitted fragments that went that far. But we could measure even that distant a relationship, albeit with less certainty.)

But it's most likely that whatever molecule it uses for a replicator would be something not related to our nucleic acids. For one thing, the major solvents appear to be non-polar rather than polar, so anything water-based would be insoluble, where things that are lipid based would tend to be soluble. Also, the reaction rate is very temperature dependent, so it would be probable that the major chemicals of life on Titan would be unstable at STP (standard temperature and pressure).

If you're like me (and most serious scientists, I gather) and believe life on Earth formed spontaneously, then it's reasonable enough to assume it can happen again. We have absolutely zero ideas how easy this is to happen, so there's no good reason to claim it can't be happening all the time.

If you're of a spiritual persuasion and believe life was kick started by some ghost or other, then you'll probably have to admit that there's no reason your omnipotent-bei

I must be misinterpreting your comment. Can you explain how crashing a probe into a celestial body has LESS contamination risk than just letting it drift off into the void?

Generally, they crash it into a celestial body that has no capability to support life and, such as the case of Jupiter, is hostile to the biological processes of what could possibly contaminate it.

No life from Earth will survive in Jupiter's atmosphere. The pressure is... extreme beyond that of the extreme on Earth.

The pressure there would be 10,000 times greater than the pressure at the deepest point in Earth's ocean. 10,000,000 Earth Atmospheres compared to 1,000 in the Marianas Trench.

Then you have the temperature. The hottest spot on Earth (the core) is about 7300K. On the liquid 'surface' of Jupiter, it is 10,000k. The most extreme of the thermophiles on Earth live in an area less than 400k. The core of Jupiter is hotter than the surface of the Sun.

If you find me something that can survive 10,000k temperatures and 10 million atmospheres I'd bow down to my new overlord.

It would be fairly easy to tell earth based contamination from native stuff. For starters, I'm not aware of any bacterium that you would find on the surface of the earth that eats hydrocarbons in that way and can live in those conditions. Below the artic ice? maybe... but in a clean room in texas? not likely.

Breathing hydrogen basically works in the opposite direction of terrestrial biochemistry. The proposed organisms are breathing hydrogen and presumably fixing it to something (say, oxides they've eaten) rather than the other way around as for Earth life.

And even if it was possible, Huygens could not have contaminated things to such a degree as to affect widespread atmospheric phenomenon.

The probe was sterilized, if I recall correctly. So it shouldn't be an issue.

Keep in mind that in the long history of the solar system it's likely that material blasted off the earth by an impact event or events has made its way to the surface of Titan. So Titan may have already been contaminated with life from earth.

I wonder if NASA has been routinely sterilizing soft landers for decades to avoid exactly the kind of thing you are wondering about.

I wonder if it might be possible to tell the difference between Earth-based contaminants and indigenous lifeforms by biochemical and (in the extremely improbable case of biochemical similarity) genetic analysis.

I wonder if it's possible to post questions on/. without knowing the first thing about a topic.

The main reason they sterilize their probes is to get "cleaner" data and no risk of contamination of future probe readings. After all, one cell is all they need to find. Any false-positive will be a disaster that they'd never live down.

The main reason they sterilize their probes is to get "cleaner" data and no risk of contamination of future probe readings. After all, one cell is all they need to find. Any false-positive will be a disaster that they'd never live down.

not to mention contaminating other components of the same probe.

at least the discovery that earth life flourished on a celestial body would be scientifically interesting. A space probe that did nothing but detect that it was self-contaminated prior to launch and can't provide useful data would be a total failure.

When I was in Jr. High, my science class had an assignment where we had to make-up a life form, based on the planet chosen's conditions and mine was Saturn. Of course my design was completely ridiculous, but the idea was pretty much close to what they're saying about Hydrogen consumption. This is pretty cool...I *heart* Saturn. "Pro'lly 'cuz it gots money with all them rings it has!" lol =P

When I was in Jr. High, my science class had an assignment where we had to make-up a life form, based on the planet chosen's conditions and mine was Saturn. Of course my design was completely ridiculous, but the idea was pretty much close to what they're saying about Hydrogen consumption. This is pretty cool...I *heart* Saturn. "Pro'lly 'cuz it gots money with all them rings it has!" lol =P

ROFL! I wonder if that's the exact same story - I've been watching the 2nd and 3rd Doctors and seeing a lot of plots and plot elements that have be directly re-used in the reboot. I haven't seen the latest season, but I can say that the quality of the horrible rubber suits has gone way up. Compare those Silurians to the original [wikia.com].

Nonense. If it weren't for us, many species (that probably deserve to) would probably have already went extinct. Does anyone think the Pandas would still be around if we weren't constantly working to try to get them to mate? It's taken more effort to get those things to reproduce than it took with Tom Cruise, for crying out loud. Seriously, if your species needs Viagra to stay viable, it's probably nature's way of saying your species just wasn't meant to be.

Sure, their reduction in number couldn't possibly have anything to do with the vast reduction in habitat caused by human activity! And their lack of hetero sex drive couldn't possibly be due to stresses caused by overcrowding and human activity, so siree! Just because pandas survived for millions of years before humans became so numerous in their vicinity doesn't imply any causal relationship between their precipitous decline and the corresponding rise in human population, it is obviously due to the fact th

Any impact we make on the environment continues to be natural in its origins.

And? You can define "natural" to be equivalent to "things that exist", but in doing so you've simply failed to say anything at all.

Deforestation, industrial waste, air pollution and so on are all "natural". So what? That doesn't mean they are good ideas, or that we shouldn't be concerned with the consequences because those consequences are "natural". "Natural" in this context doesn't mean "okay"; that connotation is often inapp

Thing is, our thought and reason allow us to monumentally outcompete every other complex organism on this planet, and yet we fail to realise that it's comparable to cutting a branch on which you sit.

I don't friggin' care about survival of other species per se, "cuddly" or otherwise. But their continuing survival would be a positive sign about our complex and quite stable (for a long time...) environment, on which also we rely for comfort.

Depends on what you mean by "outcompete". By mass, there are a lot more termites on the planet than people, and they have almost as much effect on their environment as we do. Species such as cockroaches, rats, even cats and dogs that have learned to cooperate with people seem to be doing just fine to. Even white tailed deer seem to be at historically high populations since we've eliminated their predators and we actively feed them. When you're competing with a diabolical predator such as man, being "cute" d

All I'm sayin' is "unfitness" in an environment that has been massively changed by Man in a short period of time doesn't mean that a species should be written off as a failure. Evolutionary change takes time. Deer with reflective stripes so cars don't hit them don't evolve overnight!

Insightful? I know we seem rather big and important to you.. but honestly, we're not (on universe or "anywhere") type scale. Assuming for a moment that other life forms even exist out there, and assuming that there are some at various stages of development, you REALLY TRULY can not think of anything worse then Humans?

I don't think we're as special.. either in a good way or a bad way.. as you think we are.

We are the only species that acts violently for no reason. What reason does a man have to randomly abuse or kill a woman? Look at bull fighting, or dog fighting. These are things that are human incarnations of violence for the purpose of entertainment. Animals act violently out of defense, for survival, or because of disease (rabies).

First of all, I'd contest that violence has no reason. The reason may not be good (objectively or subjectively), but I'd say that only truly insane individuals become violent for no reason.

Beyond that, there is at least one other species out there that appears to be nearly as violent as we are, and that's chimpanzees. They've been recorded attacking members of their own tribe, perhaps as punishment (though we can never be quite sure), beating them to death (I saw one harrowing attack on a documentary where they literally ripped the genitals off one). Violence is used by dominant members to put lower members in line. Most chilling of all are several documented cases of wild chimp tribes making war on neighboring tribes.

You're doing what I'd call reverse-anthropomorphization, you're ascribing to humans certain behaviors which you insist must somehow be special from other animals. It's a form of special pleading, really. Suffice it to say humans use violence as means to an end, and at least some other species use it for the same reason.

I'd say that's just an outgrowth of tribalism, and there are certainly analogs to tribalism in some other animals. A lot of human behaviors, probably almost all of them, are derived from animal behaviors. That our larger brains alter them or expand on them doesn't mean, that in some primitive form, they don't exist elsewhere.

Except that we don't. All instances of human violence can be attributed to defense, survival, territoriality, need to reproduce, etc. Just like other animals. Even our expressions of organized group violence (i.e. riots, wars, etc) are not unlike the activities of social groups in other species. Social groups of chimps and other apes will "attack" other social groups in order to obtain or defend resources. The only differences are that the resources we pursue are oil and precious metals, not bananas.

Animals most likely do lie, too - there was even a recent/. story about some antilopes using this approach during mating. I'd also argue that the act of "posturing" in many animals while being threatened ("scared"/"terrified", most likely) is also a form of lie. Insects using false color signals probably goes too far, but...

Humans demonstrably don't show much "choice" in their behavior either, statistically speaking. The most deciding factors which shape us boil down to "in what kind of environment you wer

Except that we don't. All instances of human violence can be attributed to defense, survival, territoriality, need to reproduce, etc. Just like other animals.

What a complete crock of shit.

What about rape, murder and sexual molestation? What about those sick fucks who get off torturing animals? Humans contain the most depraved bunch of members of any species on the planet. Some members do evil acts just because they feel like it. There is no gain and no reason to it.

What about my cat toying around with a mouse even though she's well fed and could easily kill it without allowing it to suffer?

Does you cat pour gasoline on animals and light them on fire? What about tying their tails together and throwing them over a power line? Only humans have the capacity for really sick acts of depravity.

You are correct in everything you say, but only in the basic form of comparison that you are using. Yes, every violent act is done for some reason or another, but because of our highly developed level of intelligence, we have a sense of right and wrong reasons.

Few would say it's wrong to violently defend yourself if you are being assaulted in an alley or in your home. On the opposite side of the coin, few would say that it is right to violently "defend" yourself if someone accidentally stepped on your foo

PS. My cat has plenty of food. Still hunts, still plays with almost dead prey even if it has visibly no intention whatsoever of eating it. But having a toy which desperately tries to escape brings very clear joy.

And it's extremely likely that, unless the aliens were non-aggressive and prone to study everything in-depth, they'd treat us similarly to the way we treat cattle - -namely, we're dumb animals unless someone's hungry, in which case we taste pretty good.

On the bright side, we have a high chance to be completelly unsuitable as food or at least quite toxic - assuming different chiralities for example.(and I'm not sure if "studying everything in-depth" would be a good thing...;) )

Strictly speaking, cattle aren't a resource, but a means of transforming resources. Quite inneficient one, even when compared to other demesticated mammals or specifically ruminants.

And they behave like that because we bred that behaviour into them. Not that it's bad per se, even from their "point of view" - heck, being tasty to us makes them one of the most evolutionary succesful large land animals. At least for now.

Titan, and Saturn system generally, is a really big thing for our distant future. People like to imagine the colonisation of Jupiter system, but the radiation belts there make it not exactly feasible; only Callisto out of 4 big moons might be fine. Saturn doesn't have this problem; is still decently close and with huge system of moons.Discovery of life on Titan might of course complicate things...OTOH, with it (if any) being probably so vastly different, there's little risk of crosscontamination in either direction.

That is its only major problem though (well, that and the atmosphere being highly toxic to humans - essentially with the addition of...Zyklon B). Other than that it offers protection, stability of conditions, "zero pressure difference" (ok, you would probably want to maintain a slight overpressure inside the base, due to toxicity - together with the cold outside that might make any leaks largely self-closing); greatly simplifying things compared to many other places, so you can concentrate easily on thermal

Occam's razor suggests that the simplest solution is usually the correct one. It does NOT mean "Reject a hypothesis because someone thinks it's not simple enough." Is there an obvious, simpler hypothesis that I'm not seeing?

Actually it doesn't matter. You test hypotheses, you don't just misuse occam's razor to assume one is right. We'll be sending another probe to Titan eventually and that will settle it.

They are titanic. When they are present you dont want to tell them that they smell, that would be racist, or humanist, or something similar, And you definately dont want to play, swim, or specially sink with them.

The original printing of the book 2001, they went to Saturn. In the film they went to Jupiter. After seeing the film Clarke thought that made more sense, so he wrote the sequel based on the film, not his book.

Titan is a young celestial body - with its own dense atmosphere and the only body until now in the solar system that has surface liquids apart from us.

Sure it can be hypothesized that since Titan is young - it probably is taking a course that Earth took millions of years ago. With the distance from Sun rendering it cold and the fact that it orbits Saturn being the primary differences.

Of course finding Life would be an enormous discovery. But if we start with what we already know - that Organic reactions are taking place on Titan's surface, and that it is a giant Organic Soup -- It gives us a huge interesting laboratory to study and experiment!

We can even direct Titan's course of life by controlled introduction of earth's anaerobic life on its surface -- since we already know a hypothesis on how our own Earth's atmosphere has evolved into the current air composition -- we can *test* and use those theories to change Titan's atmosphere, in turn not only validating our theories, but may be making Titan inhabitable like Earth!

Exciting to say the least! If only we humans can, just for a second -- stop bickering amongst ourselves and look outwards to this possibility!!

Methane itself is odorless. I suppose you could be referring to the aromatic compounds that methane-based life might excrete. You're probably just going for the cheap methane is farts joke. Yeah, imagine a Beowulf cluster of those!

The hypothesis wasn't intended to 'prove' life exists on Titan, its only an observation that one of the things we suspect would be needed, actually exist. Stop acting like such an idiot, comments like this add nothing to the conversation whatsoever. Nobody said it was proving anything. Nobody even implied it was proving anything. Im so glad you're here to discredit the scientific research being done on a moon around another planet from that big armchair of yours. Really.